Clips and Snaps
Swivels sometimes are paired with clips, (a snap that opens and closes) with one end of the clip attached to the swivel and the other end made into a clip so it can be opened and closed. This allows you to attach leaders, Snelled hooks, or lures easily without retying knots. You can also buy clips without swivels for attaching things to your line when you do not need a swivel.
Quality Clips
The better clips have a cross-locking system to make sure they don't come open when fighting a fish. The ends of the snap fold back and cross over the main part of the snap when closed, locking them into place. These kinds of clips can withstand a lot of pressure without opening.
Light wire clips are the best if they're made of strong material. The smaller, thinner ones don't add a lot of hardware to your line near the hook and won't spook the fish. Snaps should not be used with a hook when fishing for very shy species. In that case tie directly to the hook; the time spent retying knots will be well worth the added bites you'll get.
Snaps are too easy to open if bent or after a lot of use. Always replace bent or worn snaps to make sure they don't fail you when fighting a trophy fish. The cost of a new snap is not worth the chance of losing the biggest fish you've ever hooked.
Use a clip that's at least as strong at the line it's tied to. Stronger clips are usually bigger and there's no need to tie a big, strong clip to light line, but you need a strong clip on heavy line. If the line is too much stronger than the clip you'll pull it open when fighting a fish. It's best to avoid using a clip but if you need one, make sure it is tough enough so it's not the weakest point in the connection to the fish.
